Surface texture of bearing seats
The surface texture of a bearing seat has less of an impact on bearing performance compared to the dimensional and geometrical tolerances of the seat. However, the texture of the mating surfaces affects smoothing, which can reduce the interference in a fit. The surface texture should be limited to ensure the required fit is obtained.
Guideline values for the roughness profile parameter Ra are listed in table 1. These recommendations apply to ground seats, which are normally assumed for shaft seats. For housing seats, which are normally fine-turned, the Ra values may be one class higher. For applications where some loss of interference is not critical, rougher surfaces than recommended in table 1 can be used.